Idealized high-resolution simulations of a back-building convective system that causes torrential rain

Junshi Ito, Hiroshige Tsuguchi, Syugo Hayashi, Hiroshi Niino

Research output: Contribution to journalArticlepeer-review

Abstract

Record-breaking precipitation due to a back-building convective system occurred in Kyushu Island, Japan, on 5 July 2017. In this paper, a quasi-stationary back-building convective system is reproduced using a regional weather prediction model initialized with a single representative sounding in which the land-sea distribution around the observed convective system is crudely simplified. The simulated convective system and heavy precipitation are reasonably similar to observations. Horizontal resolution finer than 1 km is found to be necessary for reproducing the convective system. The area of heavy precipitation tends to shift downstream with finer horizontal resolution. The surface temperature contrasts at the northern and southern coastlines cause sea breezes and a stationary convergence line between them continuously triggers cumulus clouds. The horizontal convergence near the surface is further enhanced by preceding cumulus clouds that cause the latent heating aloft and generate a mesoscale surface pressure depression. Vertical shear of the environmental wind is also found to be important for organizing the convective system but veering of its wind direction and a cold pool are not essential.

Original languageEnglish
Pages (from-to)117-132
Number of pages16
JournalJournal of the Atmospheric Sciences
Volume78
Issue number1
DOIs
Publication statusPublished - 2021 Jan

Keywords

  • Cloud resolving models
  • Cold pools
  • Convective clouds
  • Mesoscale systems
  • Rainfall
  • Sea breezes

ASJC Scopus subject areas

  • Atmospheric Science

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